CONTENTS xv 



PAGE 



LIST OP THE ORGANS AND TOPICS CONSIDERED IN THE TEXT, CLASSED 



ACCORDING TO THE SYSTEMS TO WHICH THEY RELATE . . 206 



Integument and Integumental Organs 206 



Skeletal System 206 



Muscular System 207 



Nervous System ......... 208 



Sense Organs 208 



Alimentary System 208 



Respiratory System 208 



Circulatory System 209 



Urinogenital Apparatus 209 



SOME ORGANS AND VESTIGES OF ORGANS WHICH SHOW REVERSION TO 



THE CONDITION OF VERY PRIMITIVE VERTEBRATE TYPES . . 210 

 CONCLUDING REMARKS . . . . . . . . .212 



GLOSSARY OF TECHNICAL ZOOLOGICAL TERMS OCCURRING IN THE TEXT 219 



INDEX 223 



